(1) Field of the Invention
This invention relates to the coupling of light from a plurality of fiber-optic channels to matching fiber-optic channels, and is directed more particularly to matching of fiberoptic channels across a rotary interface.
(2) Description of the Prior Art
A variety of fiber-optic applications require that multiple fiber channels cross a rotary interface. Previous devices to accomplish this have been based on the principle of prism derotation. Light from an array of optical fibers at one side of the device is collimated into separate beams by lenses near the output of each fiber. The beams pass through a derotation prism which is caused to rotate at half the rotational speed as the input array of fibers. The group of collimated beams at the output is stationary and couples the light into a matched array of fibers and lenses. It is necessary that the input beams be precisely aligned with the output beams. To accomplish such alignment, it has been necessary to individually align the channels. Such alignment has required the input collimated beam of each input optical fiber to be tilted in two orthogonal directions and the output collimated beam of the matching output optical fiber to be similarly tilted in two orthogonal directions.
In the above-referenced application entitled Fiber Optic Bundle and Collimator Assembly (Navy Case 76173), filed concurrently with the present application, there is disclosed a fiber-optic collimator bundle array which provides for collimating beams of multiple fibers into a bundle of separate beams, all of which are precisely co-parallel.
The provision of a fiber-optic collimator bundle array of the type disclosed in the above-referenced copending application (Navy Case 76173) makes practicable the provision of a tilt adjustment mechanism adapted to align an input beam by two tilt adjustments and an output beam by two adjustments. Inasmuch as all of the channels of a bundle are co-parallel, alignment of one of the channels results in alignment of all of the channels. However, in a tilt adjustment device for bundle collimator assemblies, it is further necessary to have facility for azimuthal rotary alignment, as well as tilt alignment.
There is thus a need for a fiber-optic rotary joint with bundle collimator assemblies which provides for simultaneous alignment of all channels and, further, provides for azimuthal alignment of opposed channels.